To make the filling, melt the chocolate in a metal bowl set over but not touching simmering water in a saucepan, just until you can stir the chocolate smooth. Remove the bowl from the heat and cool to 88°F (31°C), or until it feels neither warm nor cool when you touch a drop against your lip. Stir in the hazelnut paste until evenly combined. Sift in the confectioners’ sugar, mixing to completely incorporate it. Let the filling stand, uncovered, until it is thick and spreadable, like a thick nut paste, while you make thecake.

To make the cake, preheat the oven to 350°F (177°C) with a rack in the center of the oven. Line an 11- by 17-inch rimmed baking sheet with parchment paper; butter and flour the parchment paper.

Beat the eggs, sugar, and honey in a stand mixer with the whisk attachment for 15 minutes, beginning at medium speed and increasing to high after the ingredients are blended. Sift the flour over the top, about one-third at a time, gently folding after each addition with a large spatula to completely incorporate the flour without deflating the eggs more than necessary.

Use a small offset spatula to spread the batter in an even layer over the prepared pan. Bake until light golden all over, 8 to 10 minutes. Lift out the cake on its parchment paper and transfer it to a flat surface with a long side facing you. Trim away the crusty edges on all sides of the cake, then cut the cake into four equal sections, about 4 inches wide, marking the cake on both sides and using a straight edge to cut it evenly. Turn the cake pieces bottom side up.

Check the filling: If it is thin, stir briefly over a bowl of ice water, taking care not to slosh water into the bowl, until it is thick and spreadable, like peanut butter. While the cake is still slightly warm and pliable, divide the filling evenly among the four cake pieces, then spread it evenly over the surface of each piece. With a long side facing you, roll one filled cake tightly away from you into a long roll. Continue to roll the remaining hree pieces.

Transfer the rolls, seam side down, to a baking sheet lined with plastic wrap and refrigerate for at least 15 minutes to firm the filling. Trim the ends from the rolls to neaten them, then cut each roll into three equal segments. Return the individual rolls to the lined baking sheet, seam side down.

To make the coating, melt the dark chocolate with 2 tablespoons of the oil in a bowl set over, but not touching, simmering water in a saucepan until the chocolate is melted and smooth. Remove the saucepan from the heat, keeping the chocolate over the hot water to maintain the right consistency for dipping. Dip one of the rolls into the melted chocolate, holding it from one end and then the other to completely cover it, then hold it over the bowl to let the excess chocolate run back into the bowl. Return the roll to the lined baking sheet. Continue to coat all of the rolls. Refrigerate until set, at least 30minutes.

Line a second baking sheet with plastic wrap. Melt the white chocolate with the remaining 1 tablespoon of oil in a bowl over, but not touching, simmering water. Put the pistachios in a small bowl. If you have them, put on disposable latex gloves to keep from leaving fingerprints on the rolls. Dip one end of a roll into the white chocolate, then into the chopped pistachios; repeat to coat the other end. Transfer the roll to the newly lined baking sheet. Continue to dip the remaining rolls. Refrigerate until set, 15 to 30 minutes, before serving.

Refrigerate leftover Africani in a single layer in an airtight container for up to 1 week.

Preheat the oven to 350°F (177°C). Spread out the nuts on a rimmed baking sheet and bake for 20 to 22 minutes, until they are very dark and almost smoking.If you are using a powerful blender, such as a Blendtec or Vitamix, omit the oil unless you find you need it. For most blenders, or if using a food processor, pour in 2 tablespoons of oil, then add the warm hazelnuts. Process the nuts to make a smooth paste, occasionally scraping down the sides and pushing the nuts toward the blade as needed to keep them moving. Add a bit more oil only if needed to keep the mixture moving. Be persistent—it takes a little while to get the paste going, but once it does, it willquickly turn to a smooth paste.

To make the filling, melt the chocolate in a metal bowl set over but not touching simmering water in a saucepan, just until you can stir the chocolate smooth. Remove the bowl from the heat and cool to 88°F (31°C), or until it feels neither warm nor cool when you touch a drop against your lip. Stir in the hazelnut paste until evenly combined. Sift in the confectioners’ sugar, mixing to completely incorporate it. Let the filling stand, uncovered, until it is thick and spreadable, like a thick nut paste, while you make thecake.

To make the cake, preheat the oven to 350°F (177°C) with a rack in the center of the oven. Line an 11- by 17-inch rimmed baking sheet with parchment paper; butter and flour the parchment paper.

Beat the eggs, sugar, and honey in a stand mixer with the whisk attachment for 15 minutes, beginning at medium speed and increasing to high after the ingredients are blended. Sift the flour over the top, about one-third at a time, gently folding after each addition with a large spatula to completely incorporate the flour without deflating the eggs more than necessary.

Use a small offset spatula to spread the batter in an even layer over the prepared pan. Bake until light golden all over, 8 to 10 minutes. Lift out the cake on its parchment paper and transfer it to a flat surface with a long side facing you. Trim away the crusty edges on all sides of the cake, then cut the cake into four equal sections, about 4 inches wide, marking the cake on both sides and using a straight edge to cut it evenly. Turn the cake pieces bottom side up.

Check the filling: If it is thin, stir briefly over a bowl of ice water, taking care not to slosh water into the bowl, until it is thick and spreadable, like peanut butter. While the cake is still slightly warm and pliable, divide the filling evenly among the four cake pieces, then spread it evenly over the surface of each piece. With a long side facing you, roll one filled cake tightly away from you into a long roll. Continue to roll the remaining hree pieces.

Transfer the rolls, seam side down, to a baking sheet lined with plastic wrap and refrigerate for at least 15 minutes to firm the filling. Trim the ends from the rolls to neaten them, then cut each roll into three equal segments. Return the individual rolls to the lined baking sheet, seam side down.

To make the coating, melt the dark chocolate with 2 tablespoons of the oil in a bowl set over, but not touching, simmering water in a saucepan until the chocolate is melted and smooth. Remove the saucepan from the heat, keeping the chocolate over the hot water to maintain the right consistency for dipping. Dip one of the rolls into the melted chocolate, holding it from one end and then the other to completely cover it, then hold it over the bowl to let the excess chocolate run back into the bowl. Return the roll to the lined baking sheet. Continue to coat all of the rolls. Refrigerate until set, at least 30minutes.

Line a second baking sheet with plastic wrap. Melt the white chocolate with the remaining 1 tablespoon of oil in a bowl over, but not touching, simmering water. Put the pistachios in a small bowl. If you have them, put on disposable latex gloves to keep from leaving fingerprints on the rolls. Dip one end of a roll into the white chocolate, then into the chopped pistachios; repeat to coat the other end. Transfer the roll to the newly lined baking sheet. Continue to dip the remaining rolls. Refrigerate until set, 15 to 30 minutes, before serving.

Refrigerate leftover Africani in a single layer in an airtight container for up to 1 week.

Preheat the oven to 350°F (177°C). Spread out the nuts on a rimmed baking sheet and bake for 20 to 22 minutes, until they are very dark and almost smoking.If you are using a powerful blender, such as a Blendtec or Vitamix, omit the oil unless you find you need it. For most blenders, or if using a food processor, pour in 2 tablespoons of oil, then add the warm hazelnuts. Process the nuts to make a smooth paste, occasionally scraping down the sides and pushing the nuts toward the blade as needed to keep them moving. Add a bit more oil only if needed to keep the mixture moving. Be persistent—it takes a little while to get the paste going, but once it does, it willquickly turn to a smooth paste.